The latest insights into just how sharks are able to regenerate teeth could potentially pave the way for future development of therapies meant for humans coping with tooth loss. Discovered by scientists with the University of Sheffield, the study identifies a network of genes which enable sharks to effectively develop and regenerate new teeth throughout their lifetime. These genes allow them to replace entire rows of teeth through a systemic process similar to a conveyer belt.
While it’s been known among scientists for quite a while that certain fish like sharks and rays can develop rows of highly specialized teeth with lifelong regeneration capacities, the genetic mechanisms that actually enable this to occur have not yet been understood. Led by Dr. Gareth Fraser of the University of Sheffield’s Department of Animal and Plant Sciences, the team of researchers have identified just how the special set of epithelial cells are formed.
Referred to as the dental lamina, it is responsible for lifelong continuation of tooth development and regeneration in sharks. Though humans also possess this set of cells which ultimately facilitates the production of replacement teeth, there are only two sets formed currently (baby and adult teeth.) Subsequently, the specialized cells are lost.
The team has shown that these tooth-producing genes found in sharks have been conserved over the course of 450 million years of evolution making them a likely candidate for the very first vertebrate teeth. Such tooth genes create all vertebrate teeth ranging from sharks to mammals. However, in mammals such as humans, tooth regenerating abilities using these genes have been significantly reduced over time.
Dr. Gareth Fraser says, “We know that sharks are fearsome predators and one of the main reasons they are so successful at hunting prey is because of their rows of backward pointing, razor-sharp teeth that regenerate rapidly throughout their lifetime, and so are replaced before decay. The Jaws films taught us that it’s not always safe to go into the water, but this study shows that perhaps we need to in order to develop therapies that might help humans with tooth loss.”
Through adequate analysis of teeth from catshark embryos, researchers have characterized the expression of genes in the stages of early shark tooth formation. It was discovered that such genes actually participate in the initial emergence of shark’s teeth. They are later re-deployed for further regeneration.
According to the study’s findings, the very beginnings of sharks’ evolutionary history shows their teeth were likely regenerated and utilized as a core set of genes from members of key developmental signaling pathways. These pathways were essential for the evolution of the species to maintain capabilities of re-deploying genes necessary for replacing teeth.
Despite all of the intrigue surrounding these kings of the deep, no one has ever actually managed to...